The present invention relates to a silver salt photothermographic dry imaging material comprising a support provided thereon with a light sensitive layer containing an organic silver salt, a light sensitive silver halide, a reducing agent and a binder, and in particular to a silver salt photothermographic material characterized in a support having an improved sublayer.
In the field of graphic arts and medical treatment, there have been concerns in processing of photographic film with respect to effluent produced from wet-processing of image forming materials, and recently, reduction of the processing effluent is strongly demanded in terms of environmental protection and space savings. There has been desired a photothermographic dry imaging material for photographic use, capable of forming distinct black images exhibiting high sharpness, enabling efficient exposure by means of a laser imager or a laser image setter. Known as such a technique are thermally developable silver salt photographic materials (which are the same as photothermographic materials, as described in the present invention) comprising on a support an organic silver salt, light-sensitive silver halide and a reducing agent, as described in D. Morgan and B. Shely, U.S. Pat. Nos. 3,152,904 and 3,487,075, and D. H. Klosterboer, xe2x80x9cThermally Processed Silver Systemsxe2x80x9d in IMAGING PROCESSES and MATERIALS, Neblette""s Eighth Edition, edited by J. M. Sturge, V. Walworth, and A. Shepp (1969) page 279. The thermally developable silver salt photographic material provides a simply and environment-friendly system for users, without use of any processing solution.
These silver salt photothermographic materials are provided on a support with a light sensitive layer containing light sensitive silver halide grains as a photosensor and an organic silver salt as a silver ion source, which are thermally developed with an included reducing agent usually at a temperature of 80 to 140xc2x0 C. to form images, and a backing layer containing a dye to absorb laser light. These layers must be strongly adhered to the support not only before but also after subjected to thermal development. Silver halide photographic materials, in general, are provided a sublayer to allow the light sensitive layer, backing layer or an interlayer to be adhered to the support.
Even in silver salt photothermographic imaging materials, it is also effective to provide a sublayer to allow such layers to be adhered, however, it is necessary for design of the silver salt photothermographic materials to take into consideration inherent to the photothermographic materials and differing from conventional photographic materials which are processed with a developer solution. Specifically, comparing to conventional processing with a developer solution, heating at 80 to 140xc2x0 C. is applied at the time of thermal development, easily causing internal stress and it therefore needs to make design different from that of conventional sublayers.
Further, insufficient adhesion after subjected to thermal development often produces troubles such as abrasion mark. Even in silver salt photothermographic materials, an antistatic action is needed and a sublayer provided with electric conductivity is needed to prevent troubles specifically caused in an exposure and processing system. The sublayer functions as an adhesion promotion layer, while it needs fastness until the light sensitive layer and backing layer are coated thereon. However, it was difficult to satisfy both demands.
Furthermore, it is an object of the invention to provide a silver salt photothermographic material exhibiting superior resistance to abrasion marks even after subjected to thermal processing, and improved working resistance during the manufacturing process and storage stability.
The foregoing object can be accomplished by the following constitution:
A silver salt photothermographic imaging material comprising a support provided thereon with a light sensitive layer containing an organic silver salt, a light sensitive silver halide, a reducing agent and a binder, wherein the support has at least one sublayer on at least one side of the support, the sublayer containing a metal oxide in an amount of 5 to 50% by volume and the surface of the sublayer having a maximum height (Ry) of not more than 0.1 xcexcm.
It is preferred that the sublayer comprises at least two layers comprised of upper and lower layers, the lower layer containing an acryl copolymer; and the lower layer preferably contains a polymer having an oxazoline group.